P790: THE EXPRESSION LEVEL OF WT1 MRNA IN PATIENTS WITH IDIOPATHIC CYTOPENIA OF UNDETERMINED SIGNIFICANCE (ICUS) PROGRESSING TO MYELODYSPLASTIC SYNDROME (MDS)
Authors: X. Ye, J. Huang
Journal: HemaSphere (2022)

Background: Idiopathic cytopenia of undetermined significance (ICUS) is defined as patients with one or more unexplained cytopenia who do not meet diagnostic criteria for myelodysplastic syndrome (MDS) or another hematologic disorder. In the clinical course of ICUS, some patients eventually have typical MDS changes. Until now, there is no effective method to predict the development of the disease. Recent studies have shown that the expression level of WT1 mRNA in peripheral blood has important clinical significance in the diagnosis, occurrence, development and prognosis of MDS. At the same time, some studies have proved that there is a significant difference in the expression level of WT1 mRNA between MDS and hemocytopenia caused by other reasons. Aims: In order to clarify the clinical significance of WT1 mRNA expression in the progression of ICUS to MDS. Methods: Between April 2017 and January 2020, untreated adult patients with ICUS or lower-risk MDS were enrolled in the study. All patients detected the WT1 mRNA expression of bone marrow and peripheral blood at diagnosis. Then patients with ICUS were followed up. Every three months, the patients with ICUS detected the WT1 mRNA expression of peripheral blood, until the patient progressed to MDS. The results of WT1 transcript levels are depicted as WT1 (copies/mL)/c-ABL (copies/mL) as a percentage. Results: Total of 80 patients with ICUS and 40 patients with lower-risk MDS were enrolled. At diagnosis, the median expression level of WT1 mRNA in MDS group was 5.99 (0.08-79.27), and that in ICUS group was 0.50 (0.16-22.48). There was significant difference between them (P = 0.000). Then 80 patients with ICUS were followed up to January 2022. The median follow-up time was 30 months (11-54 months). 8 patients developed MDS, the progression rate was 10%, and the median progression time was 6.5 months (2-19 months). The median expression level of WT1 mRNA at the initial diagnosis in ICUS group without progressing to MDS was 0.44 (0.16-7.58), and that in progressing to MDS group was 9.44 (0.26-22.48). There was significant difference between the two groups (P = 0.031). The median expression level of WT1 mRNA was 19.185 (0.73-42.30) when MDS was diagnosed. The median maximum expression level of WT1 mRNA in peripheral blood of ICUS group without MDS was 0.98 (0.22-7.58). There was significant difference between the two groups (P = 0.007). Summary/Conclusion: The study clarified the WT1 mRNA expression status of ICUS patients. There were significant differences in WT1 mRNA expression level between patients with ICUS and lower-risk MDS, and the WT1 mRNA expression level of patients with lower-risk MDS was relatively high. The study confirmed that patients with high WT1 mRNA expression level in the patients with ICUS (WT1 mRNA expression level > 9.44) are very likely to progressing to MDS; Dynamic monitoring of WT1 mRNA expression in peripheral blood is an effective method for following-up after ICUS diagnosis. The progressive increase of WT1 mRNA expression is one of the indicators for researchers to judge the progress of ICUS to MDS.